The previous commit hoisted the lone-surrogate check to cover every value
type, but that only closes the escaped path. A raw 0xff byte inside a
quoted string — what an HTTP body carries when a client encodes text in the
wrong charset — is not an escape, so the surrogate scan never sees it, while
encoding/json still substitutes U+FFFD and reports success. NormalizeValue
then stores the original bytes, which SQLite's json_valid accepts and
Postgres jsonb refuses: the same backend divergence, reached the other way.
Found by the Codex review bot on the previous commit's own diff.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
